1. Field of the Invention
This invention relates to construction tools and more particularly, it relates to construction tools that are adapted for moving, positioning and holding a workpiece relative to a selected work area.
2. Description of Prior Art
Various types of tools have been proposed for many years to facilitate the supporting, pushing and pulling, moving, positioning of workpieces relative to a work area. For example, the most common type of tool for this purpose is a jack which may be mechanical or hydraulic in operation. It will be apparent that the jack can move a work piece from a work area along one axis. Generally, the jack does not permit the workpiece to be rotated or moved angularly from the axis of movement of the jack. In like manner, various types of levers and prying bars have been proposed for the use in moving a workpiece in a work area. Other types of lifting devices have been a combination of the jack and the lever combined in such a fashion that the workpiece could be moved relative to the work area in one or two axis and held there manually while another function was performed on the workpiece.
These prior tools, in general, have been found inadequate wherein a workpiece of relatively great weight and size must be moved manually and within very small work areas. For example, in oil refineries and chemical plants it is quite common to have to replace a relatively large valve which may weigh, for example, 800 to 1000 pounds in a work area of a few square feet wherein only two or three workmen can conveniently perform. Usually, these areas are such that it is impossible to employ a power mechanism such as a motor crane or hydraulic lift or the like. In such instances, the workers have to manually support the valve upon a timber rack with or without jacking means to disconnect the valve, and then to move it to a position where the power equipment can grasp the valve and move it to a desired location. Reinstallation of such a valve requires a reverse of these working steps. It is quite apparent that it involves substantial physical endeavor and can be quite dangerous especially in wet surroundings.
In many instances, one pipe will have to be joined to another as by welding. For example, when a new valve or the like is to be placed into an existing piping assembly, cuts are made in the pipe and a section is removed from it. Then, flanges must be welded to the ends of the pipe for the interconnection of a valve or other pipe element into the piping assembly. For example, it is quite difficult to make connections into pipes of 8 to 12 inches in diameter which require the welding onto their ends of flanges that may weigh in the region of a thousand pounds or more. The positioning of such a flange at the end of a pipe, and especially in close quarters, is a very difficult, hard, physical task. Generally, the flange is raised by jacks to some position, then supported upon a timber platform and then welded into place. The final weld must be made in difficult quarters because the timbered support obstructs the circumferential connection of the flange to the pipeline.
In similar manner, there are many other instances where a heavy and hard to handle workpiece must be positioned at some attitude and height relative to a work surface, which may be the earth, a platform, a pipe or beam or like structure above the earth surface. It would be most advantageous to use a tool that avoids the dangerous and physical nature of conventional jacking and prying tools presently employed in the construction industry.
In accordance with the present invention, there is provided a construction tool which avoids all the difficulties with the prior devices. The tool can be used upon any selected workpiece whether the earth surface, a pipe or beam or other work area above the earth's surface. The tool is readily operated by one or two workers to move, position and hold a workpiece in a given attitude relative to the work area. More particularly, this construction tool has the ability to move a workpiece in all three planes and then hold it in a given position. In addition, the tool is readily arranged with several bases for mounting upon pipes, beams or other flat surfaces. It may be disassembled for transport or movement into a very compact work area and then readily assembled by a single operator. Other features of the present invention will be apparent from the following description of this invention.